The invention relates to a system for dispensing paper in roll form and to the method of manufacturing such a roll.
The invention relates more specifically to a system for dispensing a strip of absorbent product in the form of a roll, through rotation of the roll about an axis, of the type comprising:                a roll, formed of a wound strip of absorbent product, of substantially cylindrical shape, and axially delimited by a first lateral side and a second axially opposed lateral side;        a dispenser for dispensing the absorbent product in the form of a roll, of the type comprising a frame and a cover which is mounted such that it can move with respect to the frame, between an open position that allows the roll to be fitted inside the dispenser and a closed position for use of the roll;        means for holding and guiding the rotation of the roll with respect to the frame, which means comprise:                    a first holding element which is borne by the frame and which is able to be received axially in a first lateral housing arranged in the first side of the roll, and            a second guiding and positioning element which is borne by the cover such that it is fixed in terms of rotation and which can be received axially in a second lateral housing arranged in the second side of the roll.                        
Numerous examples of dispensing systems of this type are known.
These are, for the most part, systems which dispense one-use paper, particularly for the general public and for away from home use, known by the name of bathroom tissue, cleaning roll, kitchen towel or towel paper.
To ensure the quality of the dispensed product, some manufacturers have developed so-called “captive” systems which can accept only one type of product or a specified group of products.
There are different ways for making the system “captive”.
In particular, the prior art includes specially shaped plastic end caps, which are positioned, for example, inside a core on which the product is wound and which interact with complementary supports positioned inside the dispenser. Without these end caps, the roll cannot be put in place or cannot be used correctly.
The main drawback of this type of device is an economic one: it is necessary to manufacture additional components which are not of great benefit to the user of the system and which cannot be used once the roll is finished. These plastic components therefore represent an additional cost and increased waste when the roll is finished.
There are also known rolls including sides provided with a groove, each interacting with a special support: an ungrooved roll cannot be held in the dispenser or, alternatively, the cover of this dispenser cannot be closed because of the difference in overall dimensions between the roll without a groove and a roll with grooves.
This type of system is efficient but the manufacture of these apertures requires complex installations for converting the rolls.
To overcome this drawback, document EP-A1-1 782 722 proposes a dispensing system which comprises a strip of absorbent product in roll form and a dispenser.
The dispenser comprises a frame and a cover which is mounted to be movable with respect to the frame, between an open position that allows the roll to be fitted inside the dispenser and a closed position for the use of the roll.
The dispenser comprises a first guiding and positioning element which is borne by the cover and which can be received axially in a first housing positioned in the centre of a first side of the roll, and a second holding element which is borne by the frame and which can be received axially in a second housing positioned in the centre of a second side of the roll.
The first guiding and positioning element comprises a smooth section that is substantially frustoconical, its cross section decreasing towards the inside of the dispenser and which can be housed axially in the first associated housing of the roll.
According to that system, a roll that has no housing of frustoconical shape to complement the shape of the smooth section will prevent the cover of the dispenser from being closed because of the difference in overall dimensions between the roll without a complementary housing and a roll with a frustoconical complementary housing.
However, the smooth section can be forcibly driven into the side of the roll that has no complementary housing, by forcing the cover closed in such a way as to deform the side of the roll.
In spite of the friction between the side of the roll deformed in this way and the smooth section, there is a risk that the roll may be able to rotate about its axis of rotation by sliding on the smooth section, and that the system will then be useable, in spite of degraded operating conditions.